Lug strap assembly and method of forming same

ABSTRACT

Slots provided along substantially the entire lengths of the leg and web portions of the strap component increase its flexibility, facilitate the heat dissipation and/or provide a seat for a removable plug component. Bending of the strap into its U-shaped configuration, formation of the web slot and seating of the plug may be achieved in one operation.

, A United States Patent [151 3,646,973 Murray 1 1 Mar. 7, 1972 [54] LUG STRAP ASSEMBLY AND METHOD 2,443,111 6/1948 5 McKinley ..l39/l53 0F FORMING SAME 2,212,577 8/1940 Webster.... ....139/153 1,909,993 5/1933 Wilson...'... ....139/153 [721 may, Gamma 2,185,585 1/1940 c1311.... ....139/153 [73] Assignee: Impact Plastics, Inc., Gastonia, N.C. 2,445,744 7/1948 Moe 1 39/ 153 998,244 7/1911 Girard ....139/153 [22] 202,675 4/1878 Stone ..139/153 [21] Appl. No.: 18,951

Primary Examiner-James Kee Chi 52 us. or .Q ..139/1s3 Hem [51] Int. Cl. ..D03d 49/40 [58] 1. 19111 ofSearch ..139/153, 154, 161, 161 s; [571 ABSTRACT. 264/291 299 Slots provided along substantially the entire lengths of the leg and web portions of the strap component increase its flexibili- [56] References cued ty, facilitate the heat dissipation and/or provide a seat for a UNITED STATES PATENTS removable plug component. Bending of the strap into its U- shaped Configuration, formation of the web slot and seating of 3,348,581 10/1967 Murray ..139/153 the plug may be a hieved in one operation. 1,392,126 9/1921 Dumas ..139/153 1,406,487 2/ 1922 Powers ..139/153 4 Claims, 8 Drawing Figures PAIENIEBHAR H972 3,646,973

' SHEEI1UF2 I INVENTOR ATTORNEY COYT E. MURRAY 7 PAIENIEDMAR 7 I972 SHEET 2 OF 2 INVENTOR COYT EMURRAY BY f ATTORNEY LUG STRAP ASSEMBLY AND METHOD OF FORMING SAME BACKGROUND OF THE INVENTION This invention relates to the art of loom lug straps and their method of manufacture, such art including and being typified by US. Pat. No. 1,406,487, No. 1,909,993, No. 2,185,585, No. 2,212,577, No. 2,216,999, No. 2,443,111 and No. 3,348,581.

In an effort to increase their useful life, many modifications in the structural materials and designs of lug straps have been heretofore proposed. Some improvement has been realized by the provision of strap assemblies having plug components which are capable of being removed and replaced upon becoming worn in use. The average useful life of even a thusimproved strap assembly employed in a modern high speed loom is still relatively short, however. The strap components fail, after a limited period of use and most frequently adjacent their connections to the loom sweep sticks, even when constructed of such extremely tough and strong material as polyethylene. Such failure is believed primarily attributable to the straps relatively poor ability to accommodate the lateral or bending stresses to which they are subjected during loom operation, and/or to readily dissipate the considerable heat generated during such operation by stress and friction.

Also, despite prior recognition of the fact that strap assemblies having replaceable plug components enjoy a longer useful life, such assemblies have not met with complete commercial acceptance. Those employing bolts, rivets or like metallic members to secure the plug components in place will likely cause loom damage if through oversight the plug is not replaced before the metallic member becomes exposed. Assemblies not employing metallic connectors, but instead relying upon some type of mating relationship between the plug and strap components of the assembly, have heretofore been difficult and/or expensive to satisfactorily produce and use. The formation of a plug-receiving seat in the strap component of such assemblies, when carried out as a separate manufacturing operation, significantly increases production costs and may result in improper mating and/or misalignment of the subsequently assembled components. Additionally, the desired benefits will not be derived if the plug component is seated so insecurely as to not steadfastly retain its desired position during use, or alternatively if seated too securely to permit convenient replacement when desired.

SUMMARY OF THE INVENTION The present invention provides an improved lug strap assembly capable of extended usage without failure even in a modern high speed loom. Elongate slots provided along at least the major portion of the length of the leg and Web portions of the strap component of the assembly, and preferably along substantially the entire length of such portions, increase the strap s flexibility, facilitate heat dissipation and/or provide a seat for a removable plug component maintained securely in place during operation but adapted to be quickly and easily replaced upon becoming worn in use. The slots provided in the legs of the strap component extend completely through the same, and preferably constitute extensions of the shorter strap slots heretofore provided to receive the bolt or other similar element of the clamp by which the strap is secured to the sweep stick of a loom. In addition to facilitating heat dissipation, by increasing the straps heat-radiating surface area and by encouraging air circulation therethrough, the elongate slots increase the straps flexibility and cause more equal distribution throughout its body of particularly the lateral or bending stresses to which it is subjected during use by reason of the arcuate nature of the loom picker-stick movement. The concentration of such stresses in that portion of the strap immediately adjacent the lug strap, which concentration tends to produce premature strap failure, is especially reduced.

The slot provided at the web portion of the strap component seats a mating rib formed integral with the removable plug component of the assembly. In one embodiment the web slot extends completely through the strap, further increasing its flexibility, and also assisting in the dissipation of heat by providing an additional path along which heat generated within the plug may be conducted directly to the ambient atmosphere, within passing through the material of the strap.

In an alternative embodiment of the invention, wherein the web slot extends only partially through the strap, bending of the strap into its U-shaped configuration, formation of the web slot and seating of the plug within the latter are achieved substantially simultaneously by the use of a novel method. Manufacturing costs are significantly reduced and, perhaps even more importantly, proper alignment of and mating between the seat formed in the web portion of the strap and both the original and any subsequent replacement plug seated therewithin is insured.

ln-a more specific aspect, the invention provides a lug strap assembly having a replaceable plug component which is securely maintained in place during use of the assembly, but which upon becoming worn can be readily removed and replaced with a substitute plug by a loom fixer or other mill employee without the use of any special tools whatsoever.

Other features of the invention will be evident from the following description of an illustrative embodiment thereof, which should be read in conjunction with the accompanying drawings, in which:

FIG. 1 is a top plan view of a lug strap assembly according to the invention;

FIG. 2 is an exploded rear perspective view of the assembly of FIG. 1;

FIG. 3 is an enlarged fragmentary vertical section taken substantially along line 3-3 through the plug component and the web portion of the strap component of the assembly of FIG. 1;

FIG. 4 is an enlarged fragmentary vertical section similar to FIG. 3 through the plug and the web portion of the strap of another embodiment of the assembly;

FIGS. 5 and 6 are sequential and partially diagrammatic side elevational views illustrating a method of forming the FIG. 4 assembly in a die press;

FIG. 7 is a rear view of another embodiment of the plug component; and

FIG. 8 is a fragmentary vertical section, similar to FIGS. 3 and 4, through an assembly incorporating the FIG. 7 plug component.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to the drawings, the lug strap assembly identified in its entirety in FIG. 1 by the numeral 10 includes a strap component 12 bent into a generally U-shaped configuration and having elongate and substantially parallel leg portions l4, 16 extending freely from an integrally formed central web portion 18, and further includes a plug component 20 having a main body portion disposed between legs 14, 16 of strap 12 in engagement with web 18 thereof. As is more fully discussed hereinafter, the arrangement is preferably such that plug 20 may be removed from assembly 10 when desired, as for purposes of replacement following wearing of the plug during use. Both strap 12 and plug20 are preferably formed of polyethylene by extrusion and/or pressure-molding techniques. The use of other materials for one or the other of the components is not excluded, however. For instance, plug 20 may alternatively be formed from pressuremolded and'binder-impregnated layers of fabric, in a manner known to those skilled in the art.

Leg portions l4, 16 of strap 12 are respectively provided with serrations 22, 24 upon the inner confronting surfaces of their free end sections, and with elongate and generally parallel slots 26, 28 which extend completely through the thickness dimension of strap 12 approximately midway of its width. During use of assembly 10, serrations 22, 24 engage opposite sides of the loom sweep stick (not shown) straddled by legs l4, l6

and connected thereto as by means of a clamp including a bolt or similar element (not shown) passed through slots 26, 28. In contrast with the short slots heretofore provided for a conventional connection of the aforesaid type, the longitudinal extent of slots 26, 28 is not limited to the free end sections of legs l4, 16, upon which are provided the stick-engaging serrations 22, 24. In accordance with the present invention, slots 22, 24 extend along at least the major portion of the length of legs l4, 16 respectively, and preferably along substantially the entire lengths thereof, as shown, from closely adjacent the free ends of strap 12 to closely adjacent strap web 18. As is better shown in FIG. 2, an additional slot 30 similarly extends along substantially the entire arcuate length of strap web 18, which slot 30 also projects entirely through the thickness of strap 12 and is disposed approximately midway of its width dimension. The width of each slot 26, 28, 30 is approximately one-third the width of strap 12.

While it would seem that the elongated slots 26, 28 and 30 might so weaken strap 12 as to greatly impair its effective utilization and useful life, they have been found to produce opposite results. The longer useful life of the slotted strap 12 is believed attributable both to its increased flexibility, which minimizes failure-producing concentrations of particularly the bending stresses exerted thereon due to the arcuate path of movement of the loom picker stick, and to its enhanced ability to dissipate the heat generated during use by stress and by friction. In the latter regard, leg slots 26, 28 do more than increase the heat-radiating surface area of strap 12. Since slots 26, 28 extend longitudinally beyond the serrated end sections of legs l4, 16 which overlie the loom sweep stick, flows of heat-dissipating air pass freely through portions of their lengths during operation of the loom.

In addition to its other functions, web slot 30 is preferably utilized to assist in releasably securing plug component 20 within assembly 10. When used for this purpose, the terminal ends of slot 30 preferably slope forwardly from the outer to the inner surfaces of strap 12 at an angle of approximately 30 (see FIG. 1). The main body portion of plug 20 is provided along and centrally of its inner arcuate surface with a projecting rib 32 adapted to be closely received within slot 30 and having its ends similarly inclined or beveled. Seating of plug within strap 12, to produce the assembly 10 shown in FIG. I, may be accomplished without the use of any tools whatsoever simply by spreading legs l4, l6 outwardly a sufficient extent to pass rib 32 into slot 30 and bring the arcuate inner surface of the main body portion of plug into complemen tary engagement with the confronting forward surface of web 18. When this is accomplished and legs l4, 16 are released, their natural resilience causes the legs to return to their generally parallel positions shown'in FIG. 1, in which they and slot 30 retain plug 20 securely in place. The depth of plug rib 32 is approximately equal to the depth of slot 30, and the distance between the flat side faces of the main body of plug 20 equals the width of strap 12. When plug 20 is in place, therefore, the rearward section of assembly 10 is substantially smooth and free from depressions or projections. Since neither any part of strap 12 or any extraneous retaining element projects into plug 20, the latter may be utilized until substantially all of its main body portion has been worn completely away. At that time the worn plug 20 may be removed, and replaced by a new plug of the same configuration, simply by again spreading legs I4, 16. The inclined or beveled configuration of the ends of groove 30 and plug rib 32 reduces the amount of spreading of legs 14, 16 required for plug replacement.

Although air does not circulate through slot 30 during operation of assembly 10, such slot contributes toward heat dissipation. A relatively large percentage of the total heat to be dissipated is generated within plug 20. Slot 30 and plug rib 32 provide a direct path along which such heat can be passed directly to the ambient atmosphere, without passage through the material of web 18 of strap 12. Additional quantities of such heat are of course released directly into the atmosphere tive construction shown in FIGS 4-6, wherein elements corresponding to those of FIGS. l-3 embodiment are identified by the same reference numerals with the addition of a prime designation, may then more conveniently be employed. The

strap assembly 10' fragmentarily shown in FIG. 4 is identical to assembly 10 except that web slot 30 and plug rib 32' do not project completely through the thickness of strap 12. To insure proper retention of plug 20', however rib 32 and slot 30 extend inwardly a distance equal to at least approximately one-half the strap thickness, and preferably approximately two-thirds of such thickness, as shown.

FIGS. 5 and 6 illustrate a preferred method of economically and accurately manufacturing assembly 10. In FIG. 5 plug 20 has been previously pressure molded or otherwise formed, and a flat strap 12 has been produced, as by extrusion and/or machining techniques, so as to possess the desired serrations 22', 24 and slots 26, 28. Unless already in a workable condition, at least central portion 18' of flat strap 12' is conditioned or treated so as to increase its capability for pennanent deformation under applied stress. When strap 12' is formed as preferred of polyethylene, such conditioning may be by heating to gel temperature, within the approximate range of 225 to 325 F. At gel temperature the polyethylene becomes reasonably pliable and will with subsequent cooling retain shapes imparted to it, but remains self-supporting and will not readily adhere to other materials. The entire flat strap 12' may be heated or otherwise placed in the aforesaid condition, but as noted previously only central portion 18' thereof need be. The heated strap 12 and the unheated plug 20' are then placed as shown in FIG. 5 in a die press having a ram 34 and open face die 36 with the straps central portion 18 spanning the entrance of the die opening. Plug 20' is positioned upon the strap surface opposite die 36 for engagement by ram 34, which has a width approximately equal to the desired spacing between legs l4, 16 of the finished assembly 10'. The die press is then actuated so as to move ram 34 into die 36.

As is indicated in FIG. 6, such movement produces three results substantially simultaneously: bending of strap 12' into its desired U-shaped configuration, forming of web slot 30', and seating of plug 20. Since slot 30' is formed by plug rib 32' and receives the latter during its formation, proper seating of plug 20 occurs with little likelihood of mismating or misalignment. Additionally, the consolidation of three operations into one results in a significant reduction in manufacturing costs.

The polyethylene material displaced by plug rib 32"during formation of web slot 30' slightly increases the density and/or dimensions of web portion 18' of strap 12'. This is by no means objectionable, since it tends to increase the strength of web portion 18. A small amount of polyethylene material may on occasion be displaced outwardly from the sides of strap 12'. When this occurs, the same may be readily trimmed from strap 12 upon retraction of ram 34 and removal of the finished assembly 10' from the die pressv During the aforesaid operation, no appreciable bonding or adherence occurs between strap web portion 18' and plug 20'. This is important since adherence would impede plug replacement after wearing away of the original plug 20 following a period of use. When the components are formed of polyethylene, bonding will not occur if during the aforesaid operation strap 12 is within the gel" temperature range previously indicated and plug 20 is at ambient temperature. Components formed of other materials may require different or additional treatment or conditioning to render the strap workable and yet not have bonding occur between it and the plug.

The modified plug 20" shown in FIG. 7 differs from the plug 20' previously discussed only in the shallow circular indentations 38 provided centrally in its main body portion on opposite sides of its projecting rib 32". When plug 20" is utilized in the formation of a strap assembly by the method illustrated in FIGS. 5 and 6, cylindrical projections 40 mating with indentations 38 are also formed in the adjacent web portion of the strap component of the resulting assembly as shown in FIG. 8. The additional locking action afforded by this construction further insures that accidental displacement of the plug component will not occur during use of the assembly.

Although preferred embodiments of the invention have been specifically shown and described, this was for purposes of illustration only, and not for purposes of limitation, the scope of the invention being in accordance with the following claims.

What is claimed is: 1. A method of forming a generally U-shaped lug strap assembly including a removable plug, comprising:

providing a generally flat strap component having at least its central portion formed of polyethylene; heating at least the central portion of said strap component to facilitate permanent deformation thereof; providing a plug component resistant to deformation and resistant to bonding with the heated central portion of the strap component, said plug component having a surface for forming a plug seating recess in the strap component; positioning the heated central portion of the strap component between an open face die and the plug component; and forcing the plug component against the strap and into the die to substantially simultaneously bend the strap component into U-shaped configuration about the plug and form in the strap component a recess removably seating the plug component.

2. A method as in claim I, wherein the plug component surface for forming a plug seating recess in the strap component comprises an elongate rib projecting from said plug, and the recess formed in the strap component mates with and receives the plug rib. I

3. A method as in claim 1, wherein the central portion of the strap component is heated to a temperature within the approximate range of from 225 F. to 325 F.

4. A method as in claim 3, wherein the plug component is at ambient temperature.

It =l 

1. A method of forming a generally U-shaped lug strap assembly including a removable plug, comprising: providing a generally flat strap component having at least its central portion formed of polyethylene; heating at least the central portion of said strap component to facilitate permanent deformation thereof; providing a plug component resistant to deformation and resistant to bonding with the heated central portion of the strap component, said plug component having a surface for forming a plug seating recess in the strap component; positioning the heated central portion of the strap component between an open face die and the plug component; and forcing the plug component against the strap and into the die to substantially simultaneously bend the strap component into Ushaped configuration about the plug and form in the strap component a recess removably seating the plug component.
 2. A method as in claim 1, wherein the plug component surface for forming a plug seating recess in the strap component comprises an elongate rib projecting from said plug, and the recess formed in the strap component mates with and receives the plug rib.
 3. A method as in claim 1, wherein the central portion of the strap component is heated to a temperature within the approximate range of from 225* F. to 325* F.
 4. A method as in claim 3, wherein the plug component is at ambient temperature. 